Question

How is silver extracted from argentite?

Answer 1

Extraction of Silver from the Argentite ore: Silver is extracted from the argentite ore by the Mac Arthur and Forrest's cyanide process.
The various steps involved in this process are 1. Concentration : The crushed ore is Concentrated by froth floatation process.
2. Treatment of the ore With NaCN : The . concentrated ore is treated with 0.4 - 0.6% solution of sodium cyanide for several hours. The Mixture is continuously agitated by a current of air, So that Ag present in the or is converted into soluble sodium argento complex.
$A{g}_{2}S+4NaCN\to \underset{\left(soluble\right)}{\underset{Sodiumargentocyanide}{2Na\left[Ag\right(CN{)}_2]+N{a}_{2}S}}$
3. Precipitation of silver : The solution containing sodium argentocyanide is filtered to remove insoluble impurities and filtrate is treated with zinc dust, silver gets precipitated.
$2Na\left[Ag\right(CN{)}_2]+Zn\to N{a}_2[Zn\left(CN{)}_4\right]+2Ag\downarrow$
4. Electrolytic reaping : The impure silver is further purified by electrolytic refining. The impure silver is made the anode while a thin sheet of pure silver act as the cathode. The electrolyte is silver nitrate acidified with 1% nitric acid. On passing electricity pure silver gets deposited at the cathode.